WOODSTOCK — A writer from Pomfret says a coup is going on in America right now as we speak.

According to William Arkin, the rights and freedoms guaranteed under the Constitution are eroding in an age of concocted fear and de facto military authority. He will speak about secrecy, surveillance, government law-breaking and more at 4 p.m. Saturday at the fifth annual Bookstock Festival on the green in Woodstock.

Arkin will preview his latest book “American Coup: How a Terrified Government Is Destroying the Constitution.” The book’s publisher is Little, Brown and Company and a publication date of Sept. 10 has been set.

Arkin has over 35 years experience in national intelligence issues. He served in Army intelligence in West Berlin during the Cold War and wrote more than a dozen books, including the national best seller “Top Secret America” with Washington Post reporter Dana Priest.

In “American Coup,” Arkin says that a group of high-level officials within the national security establishment is undermining the Constitution. Arkin argues that no president in recent history has done anything to stop the abuse of power and that every aspect of civilian life has been militarized by national security programs.

Arkin said he hopes someday Americans will see through the facade and take steps to restore the Constitution.

“It’s not a conspiracy or a Dick Cheney like cabal. It’s not an evil group of people, but more like Wall Street. It doesn’t have a leader or a particular geographic location but it’s the totality of the interests of an interested class ... that every president from Harry Truman to Barack Obama has given them the authority to prepare for major calamities that are assured to occur,” Arkin said.

There were several major developments this summer on surveillance, government secrets and whistle-blowing. Former National Security Agency contractor Edward Snowden revealed several classified NSA and British spying programs this spring to Glenn Greenwald of “The Guardian.”

Snowden leaked espionage activities conducted in foreign countries, telephone data and information on American and British surveillance programs. U.S. government officials claim he broke the law, while many Americans consider Snowden a hero, according to a recent poll by Pew Research Center and USA Today.

Arkin didn’t say whether Snowden was a hero, but he is watching all of the latest developments closely and hopes it will not lead to more government power.

“Whether he will go for espionage or for harming national security remains to be seen,” Arkin said. “It’s an interesting question because as someone who worked in the field, just because they say something is secret, doesn’t mean that it is and just because they really believe a secret was revealed doesn’t necessarily mean it did damage to national security. The government still has to prove (Snowden) did damage.”

Advance copies of “American Coup” will not be for sale Saturday, but Arkin said his previous books will be. For more information on Arkin and other writers speaking at this year’s Bookstock visit www.bookstockvt.org/2013-events.